Self-acting valve for compressors and the like.



No. 867,619. 1 PATENTED 0w. 8, 1907.

, F. STRNAD. SELF ACTING VALVE FOR commzssons AND THE LIKE.

APPLIOATION FILED MAB. 29, 190B.

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FERDINAND STRNAD, OF SGHMARGENDORF, GERMANY.

SELF-ACTING VALVE FOR COMPRESSORS AND THE LIKE.

Specification of Letters Patent.

Patented Oct. 8, 1907.

Application filed March 29, 1906. Serial No. 308,763.

To all whom it may concern:

Be it known that I, FERDINAND STRNAD, a subject of the Austrian Emperor,residence 8 Sulzaerstrasse, Schmargendorf, near Berlin, Germany, haveinvented certain new and useful Improvements in Self-Acting Valves forCompressors and the Like, of which the following is a specification.

The present invention relates to improvements in self-acting valve forcompressors, and the like which allow of a long stroke of the valves,even when the machine is running with a high speed or shows the highestnumber of revolutions and which nevertheless can be brought to the seatin a completely silent manner and are lifted therefrom withoutover-pressure 't'. e. in a relieved manner. For this purpose I" use avery light pre-closing valve and a suitable buffer or cushioning devicefor a silent closure, whereby pressure is accumulated, in order torelieve the valve for the following lift, and I further combine with thebuffer device one or more relief valves which give free access to theelastic fluid when the valve is being lifted.

On the accompanying drawing I have shown the invention.

Figure 1 is a vertical sectional view of a valve corresponding to mysaid invention, in the form of a pressure valve of a compressor, blower,vacuum pump or Fig. 2 is a similar view of the buffer device on a largerscale. Fig. 3 is a vertical sectional view of a modification of Fig. 1.

The valve a the weight of which should be as small as possible is turnedup on its edge and prevents the elastic fluid from flowing back from thepressure space it, when approaching its closing position, as soon as theports (1 have been closed.

With the valve a a buffer plate tis rigidly connected by means of thespindle s which buffer plate t, simultaneously with the beginning of thepre-closure, enters the narrow bore of the valve chamber and compressesthe elastic-fluid. When. the piston has reached its dead point in thecylinder, the pre-closing of the valve begins, whereupon the lattercontinues its movement during the return stroke of the piston. As thepressure in the cylinder quickly diminishes, until it reaches thesuction-tension, the whole difference of the pressure between thistension and the tension in the chamber la is available for compressingin the buffer-chamber B the elastic fluid to such a degree that not onlythe valve is silently closed upon its seat, but also an excess ofpressure is accumulatedsuificient for relieving the valve at its nextlift; consequently the lifting of the valve takes place quickly and atthe right moment, when the elastic fluid is sufficiently compressed inthe cylinder. The relief valves 1" in the cylinder open automatically,so that the elastic fluid may freely enter the space B. By means of thebore 9 the pressure over the plate t and in the space 70 is equalized.

In the modified form shown in Fig. 3 the effect of the pressure bufferjust described is increased by the addition of a suction buffer b whichworks simultaneously with the pressure buffer. The cylindrical part ofthe valve or is somewhat higher, so that it forms a space or chamber 1)above the valve. Upon the valve a and the buffer plate t rigidlyconnected thereto being lifted, the elastic fluid lifts the reliefvalves 1' and is forced from the buffer space b through the bores c tothe buffer space B and thence flows through the bore g to the pressurespace k as soon as the buffer plate thas left the narrow bore of thevalve chamber. When the valve returns to its seat the pressure buffer Bacts in the same manner as above described, while in space I) anunder-pressure is formed, because the elastic fluid is prevented bymeans of the relief valves 7* from passing to the space I).

I am aware that it'is known to use compressor valves with buffers. Butvalves of this kind are useless without a pre-closing device, becausethe closing takes place slowly (or creepingly) under constant back-flowof the elastic fluid to the cylinder and whereby the suction to thecylinder is prevented. Moreover there are no relief valves andconsequently the re-openings of the valve takes place with aconsiderable over-pressure thereon. The well known liquid buffers arenot suited for increasing the tension for the following lifting of thevalve, because liquids are uncompressible. also been proposed to arrangethe buffers outside the valve chamber; but the stufiing box necessary inthis case makes the working of self-acting valves of this kindunreliable, especially when the machine runs with high speed. With valvegears of steam engines buffers arranged inside the valve chamber havealready been proposed, but the lifting of the valve of the same iseffected by the gear itself, so that relief valves are unnecessary.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed I declare thatwhat I claim is:

1. In compressors and the like, the combination with a cylinder open atboth ends and flushing at one end with the inside of the workingcylinder and provided in its wall with discharge-apertures, of adisk-valve seated in said cylinder and provided round its periphery witha cylindrical projection which is guided in said cylinder and is adaptedto uncover the discharge apertures in the latter, a cap closing theother end of said cylinder and extending through same so as to leave anannular narrow space for the cylindrical extension of said disk-valveand a chamber for the play of the latter, said cap having a central holeand being bored to form a cylinder, a cushioning piston reciprocating inthe cylindrical bore of said cap, a stem passing through the centralhole of said cap and rigidly connecting said disk-valve with saidpiston, a spring disposed in the working cylinder and adapted to forcesaid piston towards the bottom of said cap, and relieving means in saidcap and adapted to open towards said piston under the pressure of thefluid within the chamber between said disk-valve and said cap.

It has,

2. In compressors and the like, the combination with a cylinder open at.both ends and flushing at one end with the inside of the workingcylinder and provided in its wall with discharge-aperturcs, of adislvvalve seated in said cylinder and provided round its periphery witha cylindrical projection which is guided in said cylinder and is adaptedto uncover its discharge-apertiures upon the lifting of the valve, a capclosing the other end of said cylinder and extending through same so asto leave an annular narrow space for the cylindrical extension of saiddisk valve and a chamber for the play of the latter, said cap having acentral hole and being bored to form a cylinder, a cushioning pistonreciprocating in the cylindrical bore of said cap, a stem passingthrough the central hole 0t 15 said cap and rigidly connecting saiddislvvalve with said In testimony whereof. I have hereunto set my handin 9 presence of two subscribing witnesses.

FERDINAND S'iltNAl). Witnesses Vnvronm STHXAD, EMIL MiiLLnn.

